After the recent US Supreme Court ruling legalising same-sex marriage (SSM) throughout that country, a claim was recently brought up on a Wikipedia talk page that more than one billion people now live in countries (or states/provinces) where SSM is legal. I thought I'd check out the numbers, and update my old graph showing how this has changed over time.

As “the data guy” for the Democratic Alliance, naturally my job involves working with election result data. This post is a collection of mildly interesting facts I've learned about the 2014 elections in the course of my work. I'll start off with a quite surprising fact: the location of the busiest voting station.

My post yesterday discussed the mean centres of population of South Africa and its provinces. The mean centre is (relatively) easy to calculate, but it may not be the most useful type of population centre. It is essentially an arithmetic mean, which means that outliers can have a massive effect on the centre. It minimizes the average square of distance from the centre, not the average distance from the centre. The centre that does minimize the average distance is called the geometric median, and it is not quite so simple to calculate, since there is no closed form solution. But it can be done!

At some point in school, we South Africans are told that the official decimal separator is the comma.¹ Most of us then proceed to ignore this—at least in English use²—because it differs from the decimal point used in the rest of the English-speaking world, and thereby creates confusion. Thankfully, the maintainers of the glibc locale data—and thus the number formats used in Linux systems—agree with me on this question, and the South African English locale uses the decimal point.

I've drawn some maps showing the percentage-point change between the 2009 and 2014 elections in the vote share of the major parties (or, in the case of COPE, formerly major parties). Because municipal boundaries have changed a bit, I had to recalculate the 2009 results for the 2014 boundaries, by assigning the voting districts from 2009 to wards from 2014. In the cases where a 2009 VD was spread across multiple 2014 municipalities, I assigned it according to the location of the voting station.

The detailed 2014 election results map promised in my last post is live! It has all the features of the 2009 map, plus you can see the results from both the national and the provincial ballots. As before, you can zoom right down to street level and see the results for individual voting districts.